numam-dpdk/drivers/net/tap/rte_eth_tap.c

/*-
 *   BSD LICENSE
 *
 *   Copyright(c) 2016 Intel Corporation. All rights reserved.
 *   All rights reserved.
 *
 *   Redistribution and use in source and binary forms, with or without
 *   modification, are permitted provided that the following conditions
 *   are met:
 *
 *     * Redistributions of source code must retain the above copyright
 *       notice, this list of conditions and the following disclaimer.
 *     * Redistributions in binary form must reproduce the above copyright
 *       notice, this list of conditions and the following disclaimer in
 *       the documentation and/or other materials provided with the
 *       distribution.
 *     * Neither the name of Intel Corporation nor the names of its
 *       contributors may be used to endorse or promote products derived
 *       from this software without specific prior written permission.
 *
 *   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 *   "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 *   LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 *   A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 *   OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 *   SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 *   LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 *   DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 *   THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 *   (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 *   OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#include <rte_mbuf.h>
#include <rte_ethdev.h>
#include <rte_malloc.h>
#include <rte_vdev.h>
#include <rte_kvargs.h>

#include <sys/types.h>
#include <sys/stat.h>
#include <sys/socket.h>
#include <sys/ioctl.h>
#include <sys/mman.h>
#include <unistd.h>
#include <poll.h>
#include <arpa/inet.h>
#include <linux/if.h>
#include <linux/if_tun.h>
#include <linux/if_ether.h>
#include <fcntl.h>

/* Linux based path to the TUN device */
#define TUN_TAP_DEV_PATH        "/dev/net/tun"
#define DEFAULT_TAP_NAME        "dtap"

#define ETH_TAP_IFACE_ARG       "iface"
#define ETH_TAP_SPEED_ARG       "speed"

#ifdef IFF_MULTI_QUEUE
#define RTE_PMD_TAP_MAX_QUEUES	16
#else
#define RTE_PMD_TAP_MAX_QUEUES	1
#endif

static struct rte_vdev_driver pmd_tap_drv;

static const char *valid_arguments[] = {
	ETH_TAP_IFACE_ARG,
	ETH_TAP_SPEED_ARG,
	NULL
};

static int tap_unit;

static struct rte_eth_link pmd_link = {
	.link_speed = ETH_SPEED_NUM_10G,
	.link_duplex = ETH_LINK_FULL_DUPLEX,
	.link_status = ETH_LINK_DOWN,
	.link_autoneg = ETH_LINK_SPEED_AUTONEG
};

struct pkt_stats {
	uint64_t opackets;		/* Number of output packets */
	uint64_t ipackets;		/* Number of input packets */
	uint64_t obytes;		/* Number of bytes on output */
	uint64_t ibytes;		/* Number of bytes on input */
	uint64_t errs;			/* Number of error packets */
};

struct rx_queue {
	struct rte_mempool *mp;		/* Mempool for RX packets */
	uint16_t in_port;		/* Port ID */
	int fd;

	struct pkt_stats stats;		/* Stats for this RX queue */
};

struct tx_queue {
	int fd;
	struct pkt_stats stats;		/* Stats for this TX queue */
};

struct pmd_internals {
	char name[RTE_ETH_NAME_MAX_LEN];	/* Internal Tap device name */
	uint16_t nb_queues;		/* Number of queues supported */
	struct ether_addr eth_addr;	/* Mac address of the device port */

	int if_index;			/* IF_INDEX for the port */

	struct rx_queue rxq[RTE_PMD_TAP_MAX_QUEUES];	/* List of RX queues */
	struct tx_queue txq[RTE_PMD_TAP_MAX_QUEUES];	/* List of TX queues */
};

/* Tun/Tap allocation routine
 *
 * name is the number of the interface to use, unless NULL to take the host
 * supplied name.
 */
static int
tun_alloc(struct pmd_internals *pmd, uint16_t qid)
{
	struct ifreq ifr;
#ifdef IFF_MULTI_QUEUE
	unsigned int features;
#endif
	int fd;

	memset(&ifr, 0, sizeof(struct ifreq));

	ifr.ifr_flags = IFF_TAP | IFF_NO_PI;
	snprintf(ifr.ifr_name, IFNAMSIZ, "%s", pmd->name);

	RTE_LOG(DEBUG, PMD, "ifr_name '%s'\n", ifr.ifr_name);

	fd = open(TUN_TAP_DEV_PATH, O_RDWR);
	if (fd < 0) {
		RTE_LOG(ERR, PMD, "Unable to create TAP interface");
		goto error;
	}

#ifdef IFF_MULTI_QUEUE
	/* Grab the TUN features to verify we can work multi-queue */
	if (ioctl(fd, TUNGETFEATURES, &features) < 0) {
		RTE_LOG(ERR, PMD, "TAP unable to get TUN/TAP features\n");
		goto error;
	}
	RTE_LOG(DEBUG, PMD, "  TAP Features %08x\n", features);

	if (features & IFF_MULTI_QUEUE) {
		RTE_LOG(DEBUG, PMD, "  Multi-queue support for %d queues\n",
			RTE_PMD_TAP_MAX_QUEUES);
		ifr.ifr_flags |= IFF_MULTI_QUEUE;
	} else
#endif
	{
		ifr.ifr_flags |= IFF_ONE_QUEUE;
		RTE_LOG(DEBUG, PMD, "  Single queue only support\n");
	}

	/* Set the TUN/TAP configuration and set the name if needed */
	if (ioctl(fd, TUNSETIFF, (void *)&ifr) < 0) {
		RTE_LOG(WARNING, PMD,
			"Unable to set TUNSETIFF for %s\n",
			ifr.ifr_name);
		perror("TUNSETIFF");
		goto error;
	}

	/* Always set the file descriptor to non-blocking */
	if (fcntl(fd, F_SETFL, O_NONBLOCK) < 0) {
		RTE_LOG(WARNING, PMD,
			"Unable to set %s to nonblocking\n",
			ifr.ifr_name);
		perror("F_SETFL, NONBLOCK");
		goto error;
	}

	if (qid == 0) {
		if (ioctl(fd, SIOCGIFHWADDR, &ifr) == -1) {
			RTE_LOG(ERR, PMD, "ioctl failed (SIOCGIFHWADDR) (%s)\n",
				ifr.ifr_name);
			goto error;
		}

		rte_memcpy(&pmd->eth_addr, ifr.ifr_hwaddr.sa_data, ETH_ALEN);
	}

	return fd;

error:
	if (fd > 0)
		close(fd);
	return -1;
}

/* Callback to handle the rx burst of packets to the correct interface and
 * file descriptor(s) in a multi-queue setup.
 */
static uint16_t
pmd_rx_burst(void *queue, struct rte_mbuf **bufs, uint16_t nb_pkts)
{
	int len;
	struct rte_mbuf *mbuf;
	struct rx_queue *rxq = queue;
	uint16_t num_rx;
	unsigned long num_rx_bytes = 0;

	for (num_rx = 0; num_rx < nb_pkts; ) {
		/* allocate the next mbuf */
		mbuf = rte_pktmbuf_alloc(rxq->mp);
		if (unlikely(!mbuf)) {
			RTE_LOG(WARNING, PMD, "TAP unable to allocate mbuf\n");
			break;
		}

		len = read(rxq->fd, rte_pktmbuf_mtod(mbuf, char *),
			   rte_pktmbuf_tailroom(mbuf));
		if (len <= 0) {
			rte_pktmbuf_free(mbuf);
			break;
		}

		mbuf->data_len = len;
		mbuf->pkt_len = len;
		mbuf->port = rxq->in_port;

		/* account for the receive frame */
		bufs[num_rx++] = mbuf;
		num_rx_bytes += mbuf->pkt_len;
	}
	rxq->stats.ipackets += num_rx;
	rxq->stats.ibytes += num_rx_bytes;

	return num_rx;
}

/* Callback to handle sending packets from the tap interface
 */
static uint16_t
pmd_tx_burst(void *queue, struct rte_mbuf **bufs, uint16_t nb_pkts)
{
	struct rte_mbuf *mbuf;
	struct tx_queue *txq = queue;
	struct pollfd pfd;
	uint16_t num_tx = 0;
	unsigned long num_tx_bytes = 0;
	int i, n;

	if (unlikely(nb_pkts == 0))
		return 0;

	pfd.events = POLLOUT;
	pfd.fd = txq->fd;
	for (i = 0; i < nb_pkts; i++) {
		n = poll(&pfd, 1, 0);

		if (n <= 0)
			break;

		if (pfd.revents & POLLOUT) {
			/* copy the tx frame data */
			mbuf = bufs[num_tx];
			n = write(pfd.fd, rte_pktmbuf_mtod(mbuf, void*),
				  rte_pktmbuf_pkt_len(mbuf));
			if (n <= 0)
				break;

			num_tx++;
			num_tx_bytes += mbuf->pkt_len;
			rte_pktmbuf_free(mbuf);
		}
	}

	txq->stats.opackets += num_tx;
	txq->stats.errs += nb_pkts - num_tx;
	txq->stats.obytes += num_tx_bytes;

	return num_tx;
}

static int
tap_link_set_flags(struct pmd_internals *pmd, short flags, int add)
{
	struct ifreq ifr;
	int err, s;

	/*
	 * An AF_INET/DGRAM socket is needed for
	 * SIOCGIFFLAGS/SIOCSIFFLAGS, using fd won't work.
	 */
	s = socket(AF_INET, SOCK_DGRAM, 0);
	if (s < 0) {
		RTE_LOG(ERR, PMD,
			"Unable to get a socket to set flags: %s\n",
			strerror(errno));
		return -1;
	}
	memset(&ifr, 0, sizeof(ifr));
	snprintf(ifr.ifr_name, IFNAMSIZ, "%s", pmd->name);
	err = ioctl(s, SIOCGIFFLAGS, &ifr);
	if (err < 0) {
		RTE_LOG(WARNING, PMD, "Unable to get %s device flags: %s\n",
			pmd->name, strerror(errno));
		close(s);
		return -1;
	}
	if (add)
		ifr.ifr_flags |= flags;
	else
		ifr.ifr_flags &= ~flags;
	err = ioctl(s, SIOCSIFFLAGS, &ifr);
	if (err < 0) {
		RTE_LOG(WARNING, PMD, "Unable to %s flags 0x%x: %s\n",
			add ? "set" : "unset", flags, strerror(errno));
		close(s);
		return -1;
	}
	close(s);

	return 0;
}

static int
tap_link_set_down(struct rte_eth_dev *dev)
{
	struct pmd_internals *pmd = dev->data->dev_private;

	dev->data->dev_link.link_status = ETH_LINK_DOWN;
	return tap_link_set_flags(pmd, IFF_UP | IFF_NOARP, 0);
}

static int
tap_link_set_up(struct rte_eth_dev *dev)
{
	struct pmd_internals *pmd = dev->data->dev_private;

	dev->data->dev_link.link_status = ETH_LINK_UP;
	return tap_link_set_flags(pmd, IFF_UP | IFF_NOARP, 1);
}

static int
tap_dev_start(struct rte_eth_dev *dev)
{
	return tap_link_set_up(dev);
}

/* This function gets called when the current port gets stopped.
 */
static void
tap_dev_stop(struct rte_eth_dev *dev)
{
	tap_link_set_down(dev);
}

static int
tap_dev_configure(struct rte_eth_dev *dev __rte_unused)
{
	return 0;
}

static void
tap_dev_info(struct rte_eth_dev *dev, struct rte_eth_dev_info *dev_info)
{
	struct pmd_internals *internals = dev->data->dev_private;

	dev_info->if_index = internals->if_index;
	dev_info->max_mac_addrs = 1;
	dev_info->max_rx_pktlen = (uint32_t)ETHER_MAX_VLAN_FRAME_LEN;
	dev_info->max_rx_queues = internals->nb_queues;
	dev_info->max_tx_queues = internals->nb_queues;
	dev_info->min_rx_bufsize = 0;
	dev_info->pci_dev = NULL;
}

static void
tap_stats_get(struct rte_eth_dev *dev, struct rte_eth_stats *tap_stats)
{
	unsigned int i, imax;
	unsigned long rx_total = 0, tx_total = 0, tx_err_total = 0;
	unsigned long rx_bytes_total = 0, tx_bytes_total = 0;
	const struct pmd_internals *pmd = dev->data->dev_private;

	imax = (pmd->nb_queues < RTE_ETHDEV_QUEUE_STAT_CNTRS) ?
		pmd->nb_queues : RTE_ETHDEV_QUEUE_STAT_CNTRS;

	for (i = 0; i < imax; i++) {
		tap_stats->q_ipackets[i] = pmd->rxq[i].stats.ipackets;
		tap_stats->q_ibytes[i] = pmd->rxq[i].stats.ibytes;
		rx_total += tap_stats->q_ipackets[i];
		rx_bytes_total += tap_stats->q_ibytes[i];

		tap_stats->q_opackets[i] = pmd->txq[i].stats.opackets;
		tap_stats->q_errors[i] = pmd->txq[i].stats.errs;
		tap_stats->q_obytes[i] = pmd->txq[i].stats.obytes;
		tx_total += tap_stats->q_opackets[i];
		tx_err_total += tap_stats->q_errors[i];
		tx_bytes_total += tap_stats->q_obytes[i];
	}

	tap_stats->ipackets = rx_total;
	tap_stats->ibytes = rx_bytes_total;
	tap_stats->opackets = tx_total;
	tap_stats->oerrors = tx_err_total;
	tap_stats->obytes = tx_bytes_total;
}

static void
tap_stats_reset(struct rte_eth_dev *dev)
{
	int i;
	struct pmd_internals *pmd = dev->data->dev_private;

	for (i = 0; i < pmd->nb_queues; i++) {
		pmd->rxq[i].stats.ipackets = 0;
		pmd->rxq[i].stats.ibytes = 0;

		pmd->txq[i].stats.opackets = 0;
		pmd->txq[i].stats.errs = 0;
		pmd->txq[i].stats.obytes = 0;
	}
}

static void
tap_dev_close(struct rte_eth_dev *dev __rte_unused)
{
	int i;
	struct pmd_internals *internals = dev->data->dev_private;

	tap_link_set_down(dev);

	for (i = 0; i < internals->nb_queues; i++) {
		if (internals->rxq[i].fd != -1)
			close(internals->rxq[i].fd);
		internals->rxq[i].fd = -1;
		internals->txq[i].fd = -1;
	}
}

static void
tap_rx_queue_release(void *queue)
{
	struct rx_queue *rxq = queue;

	if (rxq && (rxq->fd > 0)) {
		close(rxq->fd);
		rxq->fd = -1;
	}
}

static void
tap_tx_queue_release(void *queue)
{
	struct tx_queue *txq = queue;

	if (txq && (txq->fd > 0)) {
		close(txq->fd);
		txq->fd = -1;
	}
}

static int
tap_link_update(struct rte_eth_dev *dev __rte_unused,
		int wait_to_complete __rte_unused)
{
	return 0;
}

static void
tap_promisc_enable(struct rte_eth_dev *dev)
{
	struct pmd_internals *pmd = dev->data->dev_private;

	dev->data->promiscuous = 1;
	tap_link_set_flags(pmd, IFF_PROMISC, 1);
}

static void
tap_promisc_disable(struct rte_eth_dev *dev)
{
	struct pmd_internals *pmd = dev->data->dev_private;

	dev->data->promiscuous = 0;
	tap_link_set_flags(pmd, IFF_PROMISC, 0);
}

static void
tap_allmulti_enable(struct rte_eth_dev *dev)
{
	struct pmd_internals *pmd = dev->data->dev_private;

	dev->data->all_multicast = 1;
	tap_link_set_flags(pmd, IFF_ALLMULTI, 1);
}

static void
tap_allmulti_disable(struct rte_eth_dev *dev)
{
	struct pmd_internals *pmd = dev->data->dev_private;

	dev->data->all_multicast = 0;
	tap_link_set_flags(pmd, IFF_ALLMULTI, 0);
}

static int
tap_setup_queue(struct rte_eth_dev *dev,
		struct pmd_internals *internals,
		uint16_t qid)
{
	struct pmd_internals *pmd = dev->data->dev_private;
	struct rx_queue *rx = &internals->rxq[qid];
	struct tx_queue *tx = &internals->txq[qid];
	int fd;

	fd = rx->fd;
	if (fd < 0) {
		fd = tx->fd;
		if (fd < 0) {
			RTE_LOG(INFO, PMD, "Add queue to TAP %s for qid %d\n",
				pmd->name, qid);
			fd = tun_alloc(pmd, qid);
			if (fd < 0) {
				RTE_LOG(ERR, PMD, "tun_alloc(%s, %d) failed\n",
					pmd->name, qid);
				return -1;
			}
		}
	}

	rx->fd = fd;
	tx->fd = fd;

	return fd;
}

static int
rx_setup_queue(struct rte_eth_dev *dev,
		struct pmd_internals *internals,
		uint16_t qid)
{
	dev->data->rx_queues[qid] = &internals->rxq[qid];

	return tap_setup_queue(dev, internals, qid);
}

static int
tx_setup_queue(struct rte_eth_dev *dev,
		struct pmd_internals *internals,
		uint16_t qid)
{
	dev->data->tx_queues[qid] = &internals->txq[qid];

	return tap_setup_queue(dev, internals, qid);
}

static int
tap_rx_queue_setup(struct rte_eth_dev *dev,
		   uint16_t rx_queue_id,
		   uint16_t nb_rx_desc __rte_unused,
		   unsigned int socket_id __rte_unused,
		   const struct rte_eth_rxconf *rx_conf __rte_unused,
		   struct rte_mempool *mp)
{
	struct pmd_internals *internals = dev->data->dev_private;
	uint16_t buf_size;
	int fd;

	if ((rx_queue_id >= internals->nb_queues) || !mp) {
		RTE_LOG(WARNING, PMD,
			"nb_queues %d too small or mempool NULL\n",
			internals->nb_queues);
		return -1;
	}

	internals->rxq[rx_queue_id].mp = mp;
	internals->rxq[rx_queue_id].in_port = dev->data->port_id;

	/* Now get the space available for data in the mbuf */
	buf_size = (uint16_t)(rte_pktmbuf_data_room_size(mp) -
				RTE_PKTMBUF_HEADROOM);

	if (buf_size < ETH_FRAME_LEN) {
		RTE_LOG(WARNING, PMD,
			"%s: %d bytes will not fit in mbuf (%d bytes)\n",
			dev->data->name, ETH_FRAME_LEN, buf_size);
		return -ENOMEM;
	}

	fd = rx_setup_queue(dev, internals, rx_queue_id);
	if (fd == -1)
		return -1;

	RTE_LOG(DEBUG, PMD, "  RX TAP device name %s, qid %d on fd %d\n",
		internals->name, rx_queue_id, internals->rxq[rx_queue_id].fd);

	return 0;
}

static int
tap_tx_queue_setup(struct rte_eth_dev *dev,
		   uint16_t tx_queue_id,
		   uint16_t nb_tx_desc __rte_unused,
		   unsigned int socket_id __rte_unused,
		   const struct rte_eth_txconf *tx_conf __rte_unused)
{
	struct pmd_internals *internals = dev->data->dev_private;
	int ret;

	if (tx_queue_id >= internals->nb_queues)
		return -1;

	ret = tx_setup_queue(dev, internals, tx_queue_id);
	if (ret == -1)
		return -1;

	RTE_LOG(DEBUG, PMD, "  TX TAP device name %s, qid %d on fd %d\n",
		internals->name, tx_queue_id, internals->txq[tx_queue_id].fd);

	return 0;
}

static const struct eth_dev_ops ops = {
	.dev_start              = tap_dev_start,
	.dev_stop               = tap_dev_stop,
	.dev_close              = tap_dev_close,
	.dev_configure          = tap_dev_configure,
	.dev_infos_get          = tap_dev_info,
	.rx_queue_setup         = tap_rx_queue_setup,
	.tx_queue_setup         = tap_tx_queue_setup,
	.rx_queue_release       = tap_rx_queue_release,
	.tx_queue_release       = tap_tx_queue_release,
	.link_update            = tap_link_update,
	.dev_set_link_up        = tap_link_set_up,
	.dev_set_link_down      = tap_link_set_down,
	.promiscuous_enable     = tap_promisc_enable,
	.promiscuous_disable    = tap_promisc_disable,
	.allmulticast_enable    = tap_allmulti_enable,
	.allmulticast_disable   = tap_allmulti_disable,
	.stats_get              = tap_stats_get,
	.stats_reset            = tap_stats_reset,
};

static int
eth_dev_tap_create(const char *name, char *tap_name)
{
	int numa_node = rte_socket_id();
	struct rte_eth_dev *dev = NULL;
	struct pmd_internals *pmd = NULL;
	struct rte_eth_dev_data *data = NULL;
	int i;

	RTE_LOG(DEBUG, PMD, "  TAP device on numa %u\n", rte_socket_id());

	data = rte_zmalloc_socket(tap_name, sizeof(*data), 0, numa_node);
	if (!data) {
		RTE_LOG(ERR, PMD, "TAP Failed to allocate data\n");
		goto error_exit;
	}

	pmd = rte_zmalloc_socket(tap_name, sizeof(*pmd), 0, numa_node);
	if (!pmd) {
		RTE_LOG(ERR, PMD, "TAP Unable to allocate internal struct\n");
		goto error_exit;
	}

	dev = rte_eth_dev_allocate(tap_name);
	if (!dev) {
		RTE_LOG(ERR, PMD, "TAP Unable to allocate device struct\n");
		goto error_exit;
	}

	snprintf(pmd->name, sizeof(pmd->name), "%s", tap_name);

	pmd->nb_queues = RTE_PMD_TAP_MAX_QUEUES;

	/* Setup some default values */
	data->dev_private = pmd;
	data->port_id = dev->data->port_id;
	data->dev_flags = RTE_ETH_DEV_DETACHABLE;
	data->kdrv = RTE_KDRV_NONE;
	data->drv_name = pmd_tap_drv.driver.name;
	data->numa_node = numa_node;

	data->dev_link = pmd_link;
	data->mac_addrs = &pmd->eth_addr;
	data->nb_rx_queues = pmd->nb_queues;
	data->nb_tx_queues = pmd->nb_queues;

	dev->data = data;
	dev->dev_ops = &ops;
	dev->driver = NULL;
	dev->rx_pkt_burst = pmd_rx_burst;
	dev->tx_pkt_burst = pmd_tx_burst;
	snprintf(dev->data->name, sizeof(dev->data->name), "%s", name);

	/* Presetup the fds to -1 as being not valid */
	for (i = 0; i < RTE_PMD_TAP_MAX_QUEUES; i++) {
		pmd->rxq[i].fd = -1;
		pmd->txq[i].fd = -1;
	}

	return 0;

error_exit:
	RTE_LOG(DEBUG, PMD, "TAP Unable to initialize %s\n", name);

	rte_free(data);
	rte_free(pmd);

	rte_eth_dev_release_port(dev);

	return -EINVAL;
}

static int
set_interface_name(const char *key __rte_unused,
		   const char *value,
		   void *extra_args)
{
	char *name = (char *)extra_args;

	if (value)
		snprintf(name, RTE_ETH_NAME_MAX_LEN - 1, "%s", value);
	else
		snprintf(name, RTE_ETH_NAME_MAX_LEN - 1, "%s%d",
			 DEFAULT_TAP_NAME, (tap_unit - 1));

	return 0;
}

static int
set_interface_speed(const char *key __rte_unused,
		    const char *value,
		    void *extra_args)
{
	*(int *)extra_args = (value) ? atoi(value) : ETH_SPEED_NUM_10G;

	return 0;
}

/* Open a TAP interface device.
 */
static int
rte_pmd_tap_probe(const char *name, const char *params)
{
	int ret;
	struct rte_kvargs *kvlist = NULL;
	int speed;
	char tap_name[RTE_ETH_NAME_MAX_LEN];

	speed = ETH_SPEED_NUM_10G;
	snprintf(tap_name, sizeof(tap_name), "%s%d",
		 DEFAULT_TAP_NAME, tap_unit++);

	if (params && (params[0] != '\0')) {
		RTE_LOG(DEBUG, PMD, "paramaters (%s)\n", params);

		kvlist = rte_kvargs_parse(params, valid_arguments);
		if (kvlist) {
			if (rte_kvargs_count(kvlist, ETH_TAP_SPEED_ARG) == 1) {
				ret = rte_kvargs_process(kvlist,
							 ETH_TAP_SPEED_ARG,
							 &set_interface_speed,
							 &speed);
				if (ret == -1)
					goto leave;
			}

			if (rte_kvargs_count(kvlist, ETH_TAP_IFACE_ARG) == 1) {
				ret = rte_kvargs_process(kvlist,
							 ETH_TAP_IFACE_ARG,
							 &set_interface_name,
							 tap_name);
				if (ret == -1)
					goto leave;
			}
		}
	}
	pmd_link.link_speed = speed;

	RTE_LOG(NOTICE, PMD, "Initializing pmd_tap for %s as %s\n",
		name, tap_name);

	ret = eth_dev_tap_create(name, tap_name);

leave:
	if (ret == -1) {
		RTE_LOG(ERR, PMD, "Failed to create pmd for %s as %s\n",
			name, tap_name);
		tap_unit--;		/* Restore the unit number */
	}
	rte_kvargs_free(kvlist);

	return ret;
}

/* detach a TAP device.
 */
static int
rte_pmd_tap_remove(const char *name)
{
	struct rte_eth_dev *eth_dev = NULL;
	struct pmd_internals *internals;
	int i;

	RTE_LOG(DEBUG, PMD, "Closing TUN/TAP Ethernet device on numa %u\n",
		rte_socket_id());

	/* find the ethdev entry */
	eth_dev = rte_eth_dev_allocated(name);
	if (!eth_dev)
		return 0;

	internals = eth_dev->data->dev_private;
	for (i = 0; i < internals->nb_queues; i++)
		if (internals->rxq[i].fd != -1)
			close(internals->rxq[i].fd);

	rte_free(eth_dev->data->dev_private);
	rte_free(eth_dev->data);

	rte_eth_dev_release_port(eth_dev);

	return 0;
}

static struct rte_vdev_driver pmd_tap_drv = {
	.probe = rte_pmd_tap_probe,
	.remove = rte_pmd_tap_remove,
};
RTE_PMD_REGISTER_VDEV(net_tap, pmd_tap_drv);
RTE_PMD_REGISTER_ALIAS(net_tap, eth_tap);
RTE_PMD_REGISTER_PARAM_STRING(net_tap, "iface=<string>,speed=N");